1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef _ASM_POWERPC_KUP_BOOKE_H_
  3#define _ASM_POWERPC_KUP_BOOKE_H_
  4
  5#include <asm/bug.h>
  6#include <asm/mmu.h>
  7
  8#ifdef CONFIG_PPC_KUAP
  9
 10#ifdef __ASSEMBLY__
 11
 12.macro kuap_check_amr	gpr1, gpr2
 13.endm
 14
 15#else
 16
 17#include <linux/sched.h>
 18
 19#include <asm/reg.h>
 20
 21static __always_inline void __kuap_lock(void)
 22{
 23	mtspr(SPRN_PID, 0);
 24	isync();
 25}
 26#define __kuap_lock __kuap_lock
 27
 28static __always_inline void __kuap_save_and_lock(struct pt_regs *regs)
 29{
 30	regs->kuap = mfspr(SPRN_PID);
 31	mtspr(SPRN_PID, 0);
 32	isync();
 33}
 34#define __kuap_save_and_lock __kuap_save_and_lock
 35
 36static __always_inline void kuap_user_restore(struct pt_regs *regs)
 37{
 38	if (kuap_is_disabled())
 39		return;
 40
 41	mtspr(SPRN_PID, current->thread.pid);
 42
 43	/* Context synchronisation is performed by rfi */
 44}
 45
 46static __always_inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long kuap)
 47{
 48	if (regs->kuap)
 49		mtspr(SPRN_PID, current->thread.pid);
 50
 51	/* Context synchronisation is performed by rfi */
 52}
 53
 54#ifdef CONFIG_PPC_KUAP_DEBUG
 55static __always_inline unsigned long __kuap_get_and_assert_locked(void)
 56{
 57	WARN_ON_ONCE(mfspr(SPRN_PID));
 58
 59	return 0;
 60}
 61#define __kuap_get_and_assert_locked __kuap_get_and_assert_locked
 62#endif
 63
 64static __always_inline void uaccess_begin_booke(unsigned long val)
 65{
 66	asm(ASM_MMU_FTR_IFSET("mtspr %0, %1; isync", "", %2) : :
 67	    "i"(SPRN_PID), "r"(val), "i"(MMU_FTR_KUAP) : "memory");
 68}
 69
 70static __always_inline void uaccess_end_booke(void)
 71{
 72	asm(ASM_MMU_FTR_IFSET("mtspr %0, %1; isync", "", %2) : :
 73	    "i"(SPRN_PID), "r"(0), "i"(MMU_FTR_KUAP) : "memory");
 74}
 75
 76static __always_inline void allow_user_access(void __user *to, const void __user *from,
 77					      unsigned long size, unsigned long dir)
 78{
 79	uaccess_begin_booke(current->thread.pid);
 80}
 81
 82static __always_inline void prevent_user_access(unsigned long dir)
 83{
 84	uaccess_end_booke();
 85}
 86
 87static __always_inline unsigned long prevent_user_access_return(void)
 88{
 89	unsigned long flags = mfspr(SPRN_PID);
 90
 91	uaccess_end_booke();
 92
 93	return flags;
 94}
 95
 96static __always_inline void restore_user_access(unsigned long flags)
 97{
 98	if (flags)
 99		uaccess_begin_booke(current->thread.pid);
100}
101
102static __always_inline bool
103__bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
104{
105	return !regs->kuap;
106}
107
108#endif /* !__ASSEMBLY__ */
109
110#endif /* CONFIG_PPC_KUAP */
111
112#endif /* _ASM_POWERPC_KUP_BOOKE_H_ */